Effect of Ni-substitution on magnetic phase transition in CuB2O4

Abstract The single crystals Cu1−xNixB2O4 with x = 0.002 ; 0.005; 0.009; 0.014 were grown by spontaneous crystallization and the magnetic properties of these crystals have been studied. The strong influence of substitution on the value of critical fields H⊥c at which the modulated states transform into a weak ferromagnetic one was observed in the temperature range 9.5–20 K. The essential change of temperature dependence of a paramagnetic susceptibility χ for Ni-doped samples in comparison with pure CuB2O4 was revealed. The modulated state was not observed in the temperature range 9.5–20 K for Ni content more than x = 0.009 .